Conventional computing devices provide several ways for enabling a user to input a choice or a selection. For example, a user can use one or more keys of an alphanumeric keyboard communicatively connected to the computing device in order to indicate a choice or selection. Additionally, a user can use a cursor control device communicatively connected to the computing device to indicate a choice. Also, a user can use a microphone communicatively connected to the computing device to audibly indicate a particular selection. Moreover, touch-sensing technology can be used to provide an input selection to a computing device or other electronic device.
Within the broad category of touch sensing technology there exist capacitive sensing touch screens and touch pads. Among commercially available capacitive sensing touch pads, there are varying patterns of sensing elements. Typical of these sensing elements are traces formed in two layers, one layer running in an x-direction and the other layer running in a y-direction. The location of a finger or other object in relation to the capacitive sensing device is determined from the x-y trace signals. However, there are disadvantages associated with this two-layer formation of x and y patterns of traces. For instance, one of the disadvantages is that the x and y patterns typically require that the x-traces and the y-traces intersect without touching. Thus, the manufacturing process becomes more complicated in order to maintain separation of traces while striving to maintain a small form factor. A further complication in the manufacture of a touch pad having two layers of traces is that of alignment of the two sets of traces.
Another commercially available sensing technology exists in which a single layer of traces is used in which each trace is connected to an area on the touch pad and then the areas are enumerated. However, there are also disadvantages associated with this commercially available sensing technology. For example, one of the disadvantages is that there is no redundancy in the sensing information, which leads to a substantial vulnerability to noise.
One other conventional sensing technology involves the use of sensing electrodes formed in triangular shapes wherein the direction of each triangle point alternates. However, there are disadvantages associated with this technique. For instance, one of the disadvantages is that as a finger (or object) moves towards the wide end of a first triangular shaped electrode and the narrow point of a second triangular shaped electrode, the narrow point electrode does not provide a quality signal because of its inherent signal to noise ratio. As such, this can be referred to as sensing geometry that induces signal to noise ratio concerns.
The present invention may address one or more of the above issues.